Between these curly braces is where we will be writing our own code that will make that button do cool things. They are similar to the tags in HTML and the curly braces in CSS. They mark the beginning and the end of the function, and without them, your code won't run correctly. The curly braces,, are also very important. In this specific scenario, it marks the beginning of what we call a callback, which is a function that gets called when an event (like the ready event) happens. The ready event makes it easy for our code to start working at just the right moment.įunction() is how we define a code routine that can be run in javascript. Quite often, we want to wait for a page to finish loading before we use javascript to manipulate its contents.
$(document).ready is an event that occurs on our document when it is fully loaded and ready to go. What is happening in this text is actually what’s called a function and you can read it a little bit like a sentence if you know how.ĭocument is a variable in javascript that gives you access to the objects and content within the web page you're viewing. Its syntax, how it’s written, is different than what we’ve been dealing with so far. This code will run after your page loads It’s what we will use to make our simple button change our background-color. In more advanced projects, Javascript will actually do complex math and calculations to do things like challenge you to a game, animate shapes and So with Javascript, you can change what things look like or how the they behave. It can look at the what’s going on in a project, (what the mouse is doing, for example) and make calculations or run logical responses that change what’s written in the HTML and CSS. Javascript, on the other-hand, can actually think. They’re static, once they’re set a certain way, they stay that way until you go back and change them. You might have noticed that HTML and CSS show exactly what’s written in between their tags and braces. Javascript is different from HTML and CSS in a big way. You can use Javascript to respond to mouse clicks, perform calculations, or animate things on the screen.
Javascript is a programming language that allows you to control how your application functions. At different stages of the cycle, some of the water is intercepted by humans or other life forms for drinking, washing, irrigating, and a large variety of other uses.So now we’re going to go someplace previous projects have not gone before: the JS tab. Almost all of the water eventually flows into the oceans or other bodies of water, where the cycle continues. Some of it evaporates, returning to the atmosphere some seeps into the ground as soil moisture or groundwater and some runs off into rivers and streams. When precipitation falls over the land surface, it follows various routes in its subsequent paths. Cloud droplets can grow and produce precipitation (including rain, snow, sleet, freezing rain, and hail), which is the primary mechanism for transporting water from the atmosphere back to the Earth’s surface. In the cool air, water vapor is more likely to condense from a gas to a liquid to form cloud droplets. For example, a cornfield 1 acre in size can transpire as much as 4,000 gallons of water every day.Īfter the water enters the lower atmosphere, rising air currents carry it upward, often high into the atmosphere, where the air is cooler. While evaporation from the oceans is the primary vehicle for driving the surface-to-atmosphere portion of the hydrologic cycle, transpiration is also significant.
Together, evaporation, transpiration, and sublimation, plus volcanic emissions, account for almost all the water vapor in the atmosphere that isn’t inserted through human activities. The gradual shrinking of snow banks in cases when the temperature remains below freezing results from sublimation.
In addition, a very small portion of water vapor enters the atmosphere through sublimation, the process by which water changes directly from a solid (ice or snow) to a gas. Plants take in water through their roots, then release it through small pores on the underside of their leaves. Most of the remaining 10% found in the atmosphere is released by plants through transpiration. Studies have revealed that evaporation-the process by which water changes from a liquid to a gas-from oceans, seas, and other bodies of water (lakes, rivers, streams) provides nearly 90% of the moisture in our atmosphere.